Product life cycle in the chemical industry starts in the laboratory and progresses through the pilot plant to large scale production. In the laboratory, handling of hazardous chemicals is done under a hood using appropriately designed ventilation systems to prevent or minimize operator exposure. Examples of such chemical fields in which hazardous materials are commonplace include pharmaceuticals, agricultural chemicals, and electronics. In large scale repetitive productions, engineering controls are designed and installed to achieve results similar to that produced in the laboratory.
However, pilot plant operations present a unique problem in this regard since vastly different products are routinely handled during the course of the year's development cycle. Flexibility in design and operation is necessary for a given level of investment in pilot plant equipment.
Traditionally, open, batch type nutsches were used in the pilot plant for solid-liquid separation. These open filters provided little protection for operators and very little emission control. Closed nutsches and other filter types were designed to overcome this problem but all contain inherent problems related to operator protection and/or emission control. Examples of such prior art filters are seen in the following:
______________________________________ U.S. Pat. No. Date To ______________________________________ 4,057,437 1977 Kracklauer directed to a belt filter 4,081,381 1978 Rosenmund et al for a nutche filter 4,328,100 1982 Moritz et al for a nutche filter 4,592,835 1986 Grieder et al for a nutche filter ______________________________________
In addition to these problems, the ability to thoroughly clean the equipment in between runs of different products, a necessary requirement of pilot plant operation, was inhibited with some of the prior art mechanical designs. Further, prior art filtration and washing apparatus for pilot plant equipment which requires handling of hazardous chemicals has generally been cumbersome, labor intensive, and otherwise expensive, due, in part, to the large number of and/or inefficient use of the design elements employed.